Skin is the largest organ of the body, accounting for almost a fifth of the weight of a normal adult. The skin performs the vital function of separating the internal components of the body from the outside environment, while also providing a permeable membrane to protect and maintain the internal organs.
Located throughout the dermal layer of skin, just below its surface, are sebaceous glands, which secrete a material composed primarily of waxes and lipids, known as “sebum”. Sebum acts to moisturize the skin in order to keep it supple and firm, and yet also sufficiently flexible to accommodate the various joints and irregular contours of the body's skeleton and internal organs. Sebum is also believed to provide certain antimicrobial benefits against airborne microbes to prevent the transmission of disease from the outside environment into the body.
While sebum performs these functional skin benefits, it also affects the aesthetic appearance of the skin. For example, the most common cause of acne is a disruption in the normal, continuous flow of sebum that is typically the result of obstructed sebaceous glands. Indeed the principal objective in anti-acne therapy is to clear existing lesions and prevent the formation of new ones. An additional objective of such skin treatment is the removal of excess sebum from the skin.
In addition to contributing to the development of skin-blemishing acne, sebum can also compromise the desired facial appearance that women seek to obtain by using cosmetics, especially facial cosmetics. Women who have imperfect complexions or whose skin appears to have an oily sheen due to the accumulation of sebum often apply a layer of facial cosmetics, known commercially as foundation, or foundation makeup, in order to give the skin a more desirable appearance. However, these cosmetics absorb sebum from the skin, causing the facial cosmetic layer to either take on a shine or become darker, giving the skin a spotty, blotched appearance. In fact, in some cases, an individual's sebum production is so high that it liquefies the cosmetic pigment layer, resulting in a rapid removal of the facial cosmetic either by physical friction and abrasion or by liquid flow. This problem is particularly acute on the eyelid as well as immediately below the eye. In order to avoid this it is necessary to frequently remove and reapply the cosmetic layer, which is a considerable inconvenience to most women. In order to avoid this it is necessary to frequently remove and reapply the cosmetic layer, which is a considerable inconvenience to most women.
In some cases, an individual's sebum production is so high that it liquefies the cosmetic pigment layer, resulting in a rapid removal of the facial cosmetic either by physical friction/abrasion or by liquid flow. This problem is particularly acute on the eyelid and/or immediately below the eye. In order to avoid this it is necessary to frequently remove and reapply the cosmetic layer, which is a considerable inconvenience to most women.
Accordingly, there is a continuing need for cosmetic compositions that provide excellent coverage and a natural skin appearance while also concealing skin imperfections or protecting skin against damage from ultraviolet radiation. Additionally, cosmetic compositions may serve as a base for such pigmented products, or can be applied over such pigmented products, thereby increasing their durability. Alternatively, cosmetic compositions may act as pure oil absorbers without the use of any other pigmented product. Such cosmetic compositions should be resistant to the deterioration caused by sebum and thereby provide long-lasting durability that lasts the entire day without the need for continued maintenance and reapplication. Additionally, these cosmetic compositions should have a smooth, comfortable, non-oily feeling when applied to the skin. There is also a need for mild, non-irritating cosmetic compositions that ameliorate or eliminate the affects of skin disorders, and reduce the blemishes and redness associated with acne.